IEC 61158-3-14:2010 pdf – Industrial communication networks – Fieldbus specifications -Part 3-14: Data-link layer service definition – Type 14 elements.
denigrated synonym for DLPDU
group DL-address
DL-address that potentially designates more than one LiLAr wirnin the extenoed link. A single DL-entity may have multiple group DL-addresses associated with a single DLSAP. A single DL-entity also may have a single group DL-address associated with more than one
micro segment
part of a network where special scheduling is implemented
multlpolnt connection
connection from one node to many nodes
NOTE Multipoini connections allow data transfer from a single publisher to be r•ceived by many subscriber nodes.
single DL-entity as it appears on one local link
number of octets from a specially designated position
ability of a system to provide a required result In a bounded time
real.time communication transfer of data in real-time
real-time Ethernet (RTE)
ISO1IEC 8802-3-based network that includes real-time communication
NOTE I Other communication can be supported, providing the real-time co.nmun,caIIon is not compromleed
NOTE 2 This definition is dedicated, but not limited, to ISOIIEC 8802-3. It could be applicable to other IEEE 802 specifications, for esampi. IEEE 802.11,
receiving DLS-user
DL-service user that acts as a recipient of DLS-user-data
NOTE A DL.e,ervic. user can be concurrently both a sending and receiving OLS-user.
temporal arrangement of a number of related operations
scheduling macrocycl.
time interval to implement a specific schedule
When the letter k) is used, the ECSME in each Type 14 device shall transfer DLS_User DATA to DIE according to the pre-conrigured timing order and priority, the DLE shall process the data and send it to PhL. so that the collision is avoided.
ECSME is the extension based on LIC defined in ISOIIEC 8802-3. For normal applications, it transfers data between DLS_User and LLC without any changing. For FRT applications, it will insert the optional DL-management tag in DLPDU to implement time-sharing scheduling policy.
ECSME does not alter the services provided by DLL to DLS_User defined in lSO/IEC 8802-3 as well as the interlace between PhL and MAC. It only provides the transmission management of the DLS_User data.
4.1.2 Transaction between DLI and Phi
The transactions between OLL and Phi defined in ISOIIEC 8802-3 are applied without any changes.
4.2 ServIces provIded by the DLL
The DLI. provides connectionless data transfer services and connection-mode data transfer services defined in ISO/IEC 8802-3, RFC 768. RFC 791 and RFC 793 protocols.
For time synchronization, the services defined in IEC 61588:2009 apply.
For deterministic communication, additional services for scheduling management are defined based on lSO!IEC 8802.3.
5 DL-management services
5.1 OvervIew
This subclause defines the constraints on the sequence in which the primitives defined in this clause may occur. The constraints determine the order in which primitives occur, but do not fully specify when they may occur. Other aspects of actual system operation, such as PhL problems affecting messages in transit, will affect the ability of a DLS-user or a DLS provider to issue a primitive at any parlicular time.
5.2 Non-perIodIc data annunciation
5.2.1 General
This service Is defined for a Type 14 device to broadcast all other devices if It has non- periodic data to be sent at the non-periodic data transferring phase.
When a Type 14 device has non-periodic data (such as alert, alarm, domain downloadlupload) to be sent, it shall broadcast the request primitive to all other nodes in the local micro- segment.
The sequence of primitive of this service is shown in Figure 3.
Priority, the length of this field is one octet,the value of this field indicates the priority of thenext non-periodic packet, if the value of this field is equal to OxFF, it is illustrated that no non-periodic packet needs to be transmitted.
Pad octets, the length of this field is 44 octets,all values of this field are set to 0x20.
Cyclic Redundancy Check value, the length is 4 octets.
5.3EndofNonPeriodicDataSendingAnnunciation service5.3.1 General
This service is defined for a Type 14 device to broadcast all other devices that the local non-periodic data has been sent and other devices can have the chance to access the network atthe non-periodic data transferring phase.
The sequence of primitive of this service is shown in Figure 3.